1) Field of the Invention
The present invention relates to a method of and an apparatus for image processing.
2) Description of the Related Art
It is common to store image data during image processing (e.g., digitized copy documents) in a memory section, such as a hard disk drive (HDD) in digital copying machines to use the data again. For example, if many copies of the original are to be formed, the throughput can be improved if data is read from the HDD plural times, instead of scanning the original several times. Another example is when copies of same original are to be formed after a lapse of time.
It also common to output image data stored in the HDD in a digital copying machine to an external device, such as a personal computer (PC), to archive the image data. This makes it possible to even process the image data or print the image data using a printer.
Because printers normally employ software-based printing and process every document as image data, it takes time to print the documents on the printer than on the digital copying machines and even the quality of the documents printed by the printer is inferior to that output from the digital copying machines. Particularly, the printers can not execute the black character process, which is the process to reproduce black characters with monochromatic black printing, performed by the digital copying machines.
One approach is to transfer the data from the PC to the HDD of the digital copying machines and print the document using the image processing resource of the digital copying machines. In this approach, high quality and faster printing can be achieved if the data transferred from the PC to the digital copying machines is in a format that is suitable to that employed in the digital copying machines. However, generally data is stored in the PCs in a joint photographic experts group (hereinafter, “JPEG”) format or the like, or subjected to color conversion process to red, green, and blue (hereinafter, “RGB”) signals or the like. Sometimes the data stored in the PC is even subjected to resolution conversion, compression or alteration of the density or color taste. If the data coming from the PC is in a format that is suitable to that employed in the digital copying machines or if the resolution of the data is inferior because of various image processing performed in the PC, the digital copying machines can not print the documents with desired image quality.